John AttiaJohn P.A. IoannidisAmmarin ThakkinstianMark McEvoyRodney J. ScottCosetta MinelliJohn ThompsonClaire Infante-RivardGordon GuyattHunter Medical Research Institute, AustraliaJohn Hunter HospitalUniversity of Ioannina, School of MedicineTufts University School of MedicineMahidol UniversityHunter Area Pathology ServiceNational Heart and Lung InstituteUniversity of LeicesterMcGill UniversityMcMaster University, Faculty of Health SciencesUniversity of Newcastle, Australia2018-09-132018-09-132009-01-07JAMA - Journal of the American Medical Association. Vol.301, No.1 (2009), 74-8115383598009874842-s2.0-58149387637https://repository.li.mahidol.ac.th/handle/20.500.14594/28215This is the first in a series of 3 articles serving as an introduction to clinicians wishing to read and critically appraise genetic association studies. We summarize the key concepts in genetics that clinicians must understand to review these studies, including the structure of DNA, transcription and translation, patterns of inheritance, Hardy-Weinberg equilibrium, and linkage disequilibrium. We review the types of DNA variation, including single-nucleotide polymorphisms (SNPs), insertions, and deletions, and how these can affect protein function. We introduce the idea of genetic association for both single-candidate gene and genome-wide association studies, in which thousands of genetic variants are tested for association with disease. We use the APOE polymorphism and its association with dementia as a case study to demonstrate the concepts and introduce the terminology used in this field. The second and third articles will focus on issues of validity and applicability. ©2009 American Medical Association. All rights reserved.Mahidol UniversityMedicineReviewSCOPUS10.1001/jama.2008.901